ON TURBULENT-DIFFUSION OF MAGNETIC-FIELDS AND THE LOSS OF MAGNETIC-FLUX FROM STARS

We discuss the turbulent diffusion of magnetic fields in astrophysical objects, and the processes leading to magnetic field flux loss from such objects. We focus in particular on the suppression of turbulent diffusion by back-reaction of magnetic fields on small spatial scales, and on the constraint imposed on magnetic flux loss by flux-freezing within stars. We show that turbulent magnetic diffusion can be suppressed even for very weak large-scale magnetic fields, so that "standard- turbulent diffusion is incapable of significant magnetic flux destruction within a star. Finally, we show that magnetic flux loss via winds is generally ineffective, no matter what the value of the effective magnetic Reynolds number is.